Go Back   Team-BHP > Under the Hood > Technical Stuff


Reply
 
Thread Tools Search this Thread
Old 12th January 2009, 15:43   #481
Senior - BHPian
 
suman's Avatar
 
Join Date: Sep 2005
Location: Gurgaon
Posts: 4,589
Thanked: 256 Times
Default

Quote:
Originally Posted by amitk26 View Post
This could be deliberate not an error , I once read on the Tyre bible link (link not handy will provide URL if I can find it again ) that manufacturers do it as a precaution to make the driver feel good while keeping the vehicle still under manageable speed so at low speeds the speed is more accurate then at higher speeds.
Amit, 155 or 165, both equally unsafe speeds wouldn't you )?
suman is offline   Reply With Quote
Old 12th January 2009, 16:17   #482
Senior - BHPian
 
ImmortalZ's Avatar
 
Join Date: Jan 2008
Location: Trivandrum
Posts: 2,124
Thanked: 82 Times
Default

Quote:
Originally Posted by amitk26 View Post
Thanks for nice explanation just one question how lean engine ( less fuel more Air ) can melt engine ? Does this mean that engines are designed in
a way such that full specific heat of diesel is not used in combustion process.

Pardon my ignorance I am not from Automobile or Mechanical Engineering background.
Compression of air is an exothermic process. That means, as air gets compressed, it release heat. However, when fuel gets compressed, it evaporates and absorbs heat. Fuel acts as a coolant inside the engine. Too lean and there isn't much of it there to siphon off some of the heat.

There are also secondary problems like detonation, which causes the fuel to explode without the spark plug due to the high temperature.

A higher octane fuel allows the fuel to stay unburned at higher temperatures, allowing higher compression ratios etc etc.

My info is specific to petrol engines by the way. I'm not too certain on how things like lean burn affect diesels.
ImmortalZ is offline   Reply With Quote
Old 12th January 2009, 16:27   #483
Senior - BHPian
 
Join Date: Jul 2008
Location: Bangalore
Posts: 2,018
Thanked: 360 Times
Default

Quote:
Originally Posted by suman View Post
Amit, 155 or 165, both equally unsafe speeds wouldn't you )?
Fully agree on that but that is what the the tyre bible page said it is a is US site I guess and pretty good for selecting rims and tyres.

Quote:
Originally Posted by ImmortalZ View Post
Compression of air is an exothermic process. That means, as air gets compressed, it release heat. However, when fuel gets compressed, it evaporates and absorbs heat. Fuel acts as a coolant inside the engine. Too lean and there isn't much of it there to siphon off some of the heat.

There are also secondary problems like detonation, which causes the fuel to explode without the spark plug due to the high temperature.

A higher octane fuel allows the fuel to stay unburned at higher temperatures, allowing higher compression ratios etc etc.

My info is specific to petrol engines by the way. I'm not too certain on how things like lean burn affect diesels.
The heat due to compression escaped my attention earlier thanks for nice explanation , I guess the same logic should be applicable to Diesels except that compression ration is many times more in CRDI engines and situation is more severe then petrols.
amitk26 is offline   Reply With Quote
Old 12th January 2009, 16:35   #484
BHPian
 
Join Date: Oct 2008
Location: Bangalore
Posts: 46
Thanked: 0 Times
Default

Quote:
Originally Posted by ram.west View Post
Thanks ak for the report. So approximately the 165kmph depicts its 155kmph as said in the manual.

But can the bull do more???

Cheers,
Ramesh
I have read about rpm/speed locks (170 ?) in Safari 2.2 elsewhere in the forum. Never tested though.

Quote:
Originally Posted by amitk26 View Post
This could be deliberate not an error , I once read on the Tyre bible link (link not handy will provide URL if I can find it again ) that manufacturers do it as a precaution to make the driver feel good while keeping the vehicle still under manageable speed so at low speeds the speed is more accurate then at higher speeds.
Could be deliberate. I too have come across such reports. But, for the end user, it's an ERROR in the gauge, nevertheless.
ak-47 is offline   Reply With Quote
Old 12th January 2009, 17:29   #485
Senior - BHPian
 
raj_5004's Avatar
 
Join Date: Jan 2008
Location: Dubai/Mumbai
Posts: 5,049
Thanked: 1,914 Times
Default

Quote:
Originally Posted by ak-47 View Post
Could be deliberate. I too have come across such reports. But, for the end user, it's an ERROR in the gauge, nevertheless.

how can they deliberately add an error only at higher speeds such that the lower speeds are accurate? if its deliberately added, it should be present in the same amount at lower speeds as well.

i feel its a shortcoming of these mechanical speedos, the higher the speed, the greater the error.
raj_5004 is offline   Reply With Quote
Old 12th January 2009, 17:36   #486
Distinguished - BHPian
 
supremeBaleno's Avatar
 
Join Date: Dec 2005
Location: Weekdays@Chennai, Weekends@Kerala
Posts: 5,093
Thanked: 1,421 Times
Default

Quote:
Originally Posted by ram.west
So approximately the 165kmph depicts its 155kmph as said in the manual. But can the bull do more???
@Ramesh, those speeds are already too dangerous for a high C.G. vehicle like yours. Especially on our kind of roads. Slow down, buddy.
supremeBaleno is offline   Reply With Quote
Old 12th January 2009, 17:55   #487
BHPian
 
ram.west's Avatar
 
Join Date: Oct 2008
Location: Chennai
Posts: 418
Thanked: 19 Times
Smile

Definitely SB . Just wanted to know how much i could max her out. And I did it in the Bangalore Highway in a pretty straight section . Usually i just cruise along between 80-120 on highways, I think thats the best range where we get max comfort and control over the vehicle.

Cheers,
Ramesh
ram.west is offline   Reply With Quote
Old 12th January 2009, 18:00   #488
Senior - BHPian
 
Join Date: May 2007
Location: Bangalore
Posts: 3,649
Thanked: 242 Times
Default

Quote:
Originally Posted by ram.west View Post
Thanks ak for the report. So approximately the 165kmph depicts its 155kmph as said in the manual.

But can the bull do more???

Cheers,
Ramesh
The official Top speed for Safari 2.2l is 160kmph, I have touched that and engine holds itself back when it starts nearing 163.

The speedo is calibrated to absorb errors unless you change the stock tyre profile.

Last edited by dadu : 12th January 2009 at 18:01.
dadu is offline   Reply With Quote
Old 12th January 2009, 18:04   #489
BHPian
 
ram.west's Avatar
 
Join Date: Oct 2008
Location: Chennai
Posts: 418
Thanked: 19 Times
Post

Thanks dadu, for the information. I'm running on stock setup only. And yes , I have no plans of doing that again. As I said I'm more comfortable in that 80-120 range.
ram.west is offline   Reply With Quote
Old 12th January 2009, 18:31   #490
Senior - BHPian
 
Join Date: Jul 2008
Location: Bangalore
Posts: 2,018
Thanked: 360 Times
Default

Quote:
Originally Posted by raj_5004 View Post
how can they deliberately add an error only at higher speeds such that the lower speeds are accurate? if its deliberately added, it should be present in the same amount at lower speeds as well.

i feel its a shortcoming of these mechanical speedos, the higher the speed, the greater the error.
Very Easy by making a non linear gauge and or in your words introducing shortcoming by design rather then by chance to give a feel good factor to driver,
Why I say this could be deliberate because the same error is not reflected in Odometer but only in Speedo while both are deriving the rotation count from same point .

Odometer is quite noticeable and user has fair idea of distances it would be foolish to make it inaccurate and may be illegal too.

EDIT : Here I am not talking about Safari in particular but considering the cars which have mechanical odometers.

You can introduce this non linear speedo error yourself by changing tyre size / profile. There will be a small error per rotation of tyre and it will keep on increasing with number of rotations per unit time so at high speed the error will be quite noticeable but this will be reflected in Odometer too.

Manufacturer can introduce this kind of error at any point in only in mechanical speedometer by using a slightly different size of gear.

Last edited by amitk26 : 12th January 2009 at 18:42.
amitk26 is offline   Reply With Quote
Old 13th January 2009, 12:56   #491
Distinguished - BHPian
 
jkdas's Avatar
 
Join Date: Sep 2005
Location: Thiruvananthapu
Posts: 9,575
Thanked: 1,234 Times
Default

Check this mod. Neat one.
Attached Images
  
jkdas is offline   Reply With Quote
Old 13th January 2009, 13:50   #492
Senior - BHPian
 
Join Date: Jul 2008
Location: Bangalore
Posts: 2,018
Thanked: 360 Times
Default

Quote:
Originally Posted by jkdas View Post
Check this mod. Neat one.
cool mod JK can you post picture from below to show how pipe is routed
and what you did fir extending it.

Probably you can attach a steel muffler extension

I saw a similar mod where Pipe was routed from the hatch / lid below number
plate avoiding bumper cutting but exhaust pipe was looking little out of the place in center.
amitk26 is offline   Reply With Quote
Old 14th January 2009, 11:23   #493
BHPian
 
Join Date: Oct 2008
Location: Delhi
Posts: 26
Thanked: 4 Times
Default

Hey,

May be mine the youngest Safari/Bull on T-BHP. Thanks to you guys specially ADC, irrespective of known niggles and issues , I went for it.
Its Cycus Grey- LX , 2500KM run and a month old.
Twice I had the hose pipe blown. I dont know the purpose or reason for this Orange coloured pipe, but when the pipe was blown Bull couldnt move more then 15KM/hr. Driving 120 KMs from Palwal to my place at 11 PM was painful. The only assurance I have is A-ONE motors will change the whole assembly if the pipe blows out again. (Is it something serious??)
A bit scared to check TSK's issues and soon will dare again to take my bull on a long drive.

Soon will post pics...
Cheers
B_t
Bull_Twin is offline   Reply With Quote
Old 14th January 2009, 14:12   #494
Senior - BHPian
 
Join Date: Jul 2008
Location: Bangalore
Posts: 2,018
Thanked: 360 Times
Default

Are you talking about Turbo hose ?

Quote:
Originally Posted by Bull_Twin View Post
Hey,

May be mine the youngest Safari/Bull on T-BHP. Thanks to you guys specially ADC, irrespective of known niggles and issues , I went for it.
Its Cycus Grey- LX , 2500KM run and a month old.
Twice I had the hose pipe blown. I dont know the purpose or reason for this Orange coloured pipe, but when the pipe was blown Bull couldnt move more then 15KM/hr. Driving 120 KMs from Palwal to my place at 11 PM was painful. The only assurance I have is A-ONE motors will change the whole assembly if the pipe blows out again. (Is it something serious??)
A bit scared to check TSK's issues and soon will dare again to take my bull on a long drive.

Soon will post pics...
Cheers
B_t
amitk26 is offline   Reply With Quote
Old 14th January 2009, 17:43   #495
BHPian
 
Join Date: Oct 2008
Location: Delhi
Posts: 26
Thanked: 4 Times
Default

No idea if its Turbo hose or what.. but its orange or red colour. The vehicle didnt accept any acceleration and if accelerator is pressed it gives loud hsssss noise.
Another issue which has been reported earlier by many guys is drifting towards left when break is applied. Hope these are not serious.
Bull_Twin is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Skoda Laura: Problems & solutions thread anandbhat Technical Stuff 1010 24th November 2016 13:48
Tata Safari - Technical Specifications & Feature List Stratos Technical Stuff 11 24th June 2011 20:48
technical aspects in technical driving ram_hyundai Technical Stuff 1 2nd February 2008 21:12


All times are GMT +5.5. The time now is 06:00.

Copyright 2000 - 2016, Team-BHP.com
Proudly powered by E2E Networks